Method of breaking rock.



Patented Apr. 23,.|90l.

3 Sheets-Shget l.

No. .672,6l6.

T. A. EDISON.

METHOD 0F BREAKING ROCK.

(Application filed July 1B 1897.) (nu Manel.)

@gli

wnNEsSES Patented Apr. 23, IQDI.

No. (572,6I6.l

T. A. Enlsou. METHOD 0F BREAKING BUCK.

i (Application led July 16, 1897.) (No lllndel.) 3 Sheets-Sheet 2.

ATTORNEY S No. 672,6l6. Patented Apr. 23, |901.

' T. A. EmsoN.

METHnn 0F BREAKING Hock.

(Application led July 16 1897. (No Model.) J

3 Sheets-Sheet V3.

WITNESSES: INVENTOR ATTORNEYS n z :ns co. morauryo.. msmnc-To. n. c.

UNITED STATES PATENT OFFICE.

THOMAS A. EDISON, OF LLEWELLYN PARK, NEW JERSEY.

METHOD OF BREAKING ROCK.

SPECIFICATION fOrmng' part 0f Letters Patent N0. 672,616, dated April 23, 1901.

i Application filed July 16, 1897. Serial No. 644,747. (No specimens.)

l'o all whom t may concern:

Be it known that LTHOMAS A. EDIsoN,a citizen of the United States, residing at Llewellyn Park, in the county of Essex and State of New Jersey, have invented a certain new and useful Improvement in Methods of Breaking Rock, (Case No. 977,) of which the following is a specification.

In the mining and milling of ore in the form of rock a very considerable expense has been addedto the cost of the mining operations by the necessity for blasting and sledging the pieces of rock, so as to reduce them in size to the point where they can be handled by stonecrushers or stamp-mills, such as are at present employed.

The object of my invention is to produce a method for the breaking of rock which will be simple and eective, will not require the hand-sledgin-g or blasting of the rock down to pieces of moderate size, and will involve the consumption of a small amount of power.

In carrying out my invention I employ a pair of rolls of massive size and weight and havingsuitably roughened or irregular surfaces-the irregular surface, for instance, be-

ing formed by providing the rolls with projections or knobs, which is the preferred construction. To these rolls I apply a small power sufcient to gradually run the rolls up to a high speed when no Work is being done, but which power may not be su fficient to start the rolls from a state of rest. The rolls are mounted side by side in a suitable frame and have a wide gap between their opposing surfaces. The rolls run in opposite directions, so that the movement of the irregular surfaces is toward each other on the top of the rolls and downward through the gap. After the rolls acquire their full speed a large piece of rock or several pieces carried by a skip will speed of the rolls, I prefer to apply the power to the rolls through slipping friction-clutches, which slip without materially reducing the speed of the driving-pulleys; but it is evident that the same result can be accom plished, although not so conveniently, by employing anysuitable device for disconnecting the rolls from the driving-shaft just before the rock is dumped upon the rolls and reconnecting them with the driving-shaft im medately after the rock is broken or even by maintaining the connection with the driving-engine of small power and allowing its speed to be reduced with that of the rolls. While another skip is being elevated into position for dum ping, the rolls will be gradually run up to their full speed. The time required to attain full speed after a rock has been broken is of course many times that required to break the rock. This interval of time is afforded by the hoisting of another skip and bringing it into position for dumping. The power applied to the rolls will be suiicient to enable them to regain their speed during this interval.

As an illustration of an efficient embodiment of my invention I will say that the pair of giant rolls which I have built and operated have, including all moving parts, a combined weight of 011e hundred and sixty-seven thousand pounds. Each roll is siX feet in diameter and iive feet long, and the gap between the rolls is fourteen inches. These lrolls are given a surface speed of about four thousand feet per minute. The speed of the drivingbelt, which operates through slipping friction, is practically constant; but the speed of the rolls is reduced about ten per cent. in the breaking of a rock and during a fraction of a second, while an interval of from twenty to forty seconds is required for the rolls to recovert-heirfullspeed. Thefriction employed is not sucient to start the rolls from a state of rest, and consequently in starting handlevers are employed. The energy of the blow which these rolls are capable of delivering is enormous. I may say that I have been able to break with these rolls single chunks of rock of the magnetic iron ore upon which I have been operating as large as six feet through and weighing as much as four or five tons. The rolls are faced with removable wearing-plates, which in the preferred con- IOO struction are provided with radially-projecting knobs, so that a rock in falling upon the rolls will be caught between the knobs on the approaching surfaces of the two rolls. Since a large rock presenting a flat surface might ride on these knobs if they were of uniform height, I provide at one or more-points (preferably two points) in the diameter of each roll a line of larger knobs, which serve to Sledge such a large rock and reduce it to such a size that it will be caught and finally forced through the rolls by the smaller knobs. This double operation of' sledging by the larger knobs and then breaking by a rolling action with the smaller knobs makes the rolls effect-` ive for the breaking of pieces as large as the distance between thecenters of the rolls.

In lthe accompanying drawings, forming a ing the rolls.

A and B are the two rolls, provided with removable wearing-plates a, which are secured] The wearing-plates have] projecting knobs c of uniform height, and at opposite points in the diameter of each roll is a line of larger knobs d. The rolls are mou nted:v in a suitable frame O. Upon the end of each; of the roll-shafts is loosely mounted a pulley F;

by bolts b, Fig. 2.

Outside of this pulley and secured by bolts f to the end of the roll-shaft is a band-wheel Gr. Around each of these band-wheels is placed a of each pulley F and pivoted thereto is a bell-;.

crank i, which is secured on opposite sides of its pivot to the ends of the friction-band H; The extreme end of the bell-crank 'L' is connected with the rod j, passing through a plate lo and carrying outside of that plate a coiled spring Z, whose tension is adjustable by means of a nut m. The driving-belt I extends from the driving-shaft to the rolls, and at the rollsl passes over an idler J, located centrally above the two pulleys F. From this idler the belt I passes over one of the pulleys and then in the opposite direction overv the other pulley and returns to the driving-shaft. The power applied through the belt I tends to drive the rolls in opposite directions, as indicated by the arrows, through the friction-ban ds H; but when a rock is dropped upon the rolls and their speed of rotation is partially arrested these friction bands slip upon the bandwheels G, and after the rock has passed through the rolls the friction-bands continue to slip until the rolls are again brought upto speed.

Referring particularly. to Fig. 1, the hop- Fig. 3 is a side ele-1 per KvopensA downwardly from the platform L, below which the rolls are located, and above this platform is located an electric crane M. The space between the platform L and the crane M is open at the front of the building. The rock to be broken is loaded on skips N, which are brought on cars to the front of the building opposite the space between the platform and the crane. The crane is run out over the cars and the hoistingchain P is lowered and its three hooks n are attached to one of the loaded skips. The skip is carried by the hoisting-chain in a horizontal position, so as not to dump its load, and is hoisted to the position shown in dotted lines in Fig. 1, when the crane is run back over the hopper. The skip is then moved to one side of the hopper and lowered until it rests on the platform at one side of the hopper. At this point the platform is provided with bars o, of Wood, upon which the skip is lowered. The two forward hoisting-hooks attached to the sides of the skip are then detached from the skip by an attendant, and the crane then pulls up on the hoisting-chain. This lifts up the rear end of the skip and tiltsit, so that its load isdumped into the hopper K, the poi'nt of the skip or its forward strengthening-rib engaging with one of the bars o, so that the skip does not slide forl. The method of breaking rock consisting in causing two independently-driven and disconnected massive bodies to travel toward veach other at a high speed, partially arresting the motion of such bodies by successively and periodically introducing charges of rock `between them, thereby breaking-the rockby `kinetic energy, and restoring the speed of such bodies during the intervals, substantially as set forth.

IOO

IIC

2. The method of breaking rock consisting in drivinga pair of independently-driven and disconnected massive rolls at a high speed by means of a small power capable of `running the rolls up to speed when no work is being done, partially arresting the motion of the rolls by successively and periodically delivrmo ering charges of rock to them, thereby breaking the rock by Vkinetic energy,.and restoring the speed of the rolls during the intervals, substantially as set forth.

This specification signed and witnessed this 'I 14th day of May, 1897.

THOMAS A. EDISON.

Witnessesz.

JNO. R.,TAYLoR, EUGENE COURAN. 

